Obvious gotcha to that is if you have a link on every blog post to jump to the most recent entry. If you were going dynamic, that info would be inserted on page generation, if you're going static then you need to update everything.
Easy solution would be to make a duplicate page like /latest.html which updates as necessary.
There are other gotchas as well; for example, on my blog I have links in my sidebar to pages for categories and tags, but the links have total post counts for the category/tag after them, so every time a new post is added at least one count will change on every page. I don't mind because the SSG I use (my own, https://github.com/pdonis/simpleblog3 ) renders fast enough to suit me; it takes about 5-6 seconds to render my entire blog.
Since the sidebar stuff or 'recent entry' links are not really important for SEO, couldn't you just load those from one static file using a bit of javascript? That's what I'm thinking of doing...
I could, but I want to keep the site entirely Javascript-free. I have experimented a bit with using iframes to load the sidebars from one static file, but I haven't gotten that to work the way I want it to.
Browsers don't seem to treat iframes the way they treat other layout elements; I have to specify the exact size (width and height) of the iframe or it won't get laid out correctly. I don't want that; I want an iframe that flows with the rest of the layout just like other box elements.
Unless the generator can keep track of what has and hasn't changed and only rebuild the changed stuff.